The invention relates to a guide or tensioning rail in a traction drive, wherein the guide or tensioning rail has at least one bearing lug with a sleeve.
Traction drives are used, among other things, for transmitting rotational movements in internal combustion engines. For example, the rotation of a crankshaft can be transmitted with the help of the traction mechanism to camshafts or secondary assemblies of a vehicle, wherein belts, bands, V belts, toothed belts, or chains are used as the traction mechanism. For guidance and also to keep the traction mechanism under a sufficient biasing tension, it is known that the traction mechanism is guided with the help of at least one guide rail and a force is exerted on the traction mechanism with at least one tensioning rail, wherein this force acts essentially perpendicular to its direction of movement, as well as into the center of the traction drive. For this purpose, the guide rails are typically mounted rigidly to another component, for example, an engine block. The tensioning rails are loaded with a spring force or by a hydraulic force and keep the traction mechanism under a sufficient biasing tension, optionally also as a function of the rotational speed of the traction mechanism, in order to prevent, among other things, jumping of the traction mechanism from a driving wheel.
A tensioning rail for a chain drive is known, for example, from DE 199 13 288 A1. It is formed from an elongated and hollow base body that is filled with a metal foam. Here, the tensioning rail can be mounted on an engine block via a bolt that passes through a receptacle borehole. The production of such a tensioning rail, however, requires considerable manufacturing-related expense due to the foaming.
Furthermore, DE 199 23 923 A1 discloses a tensioning rail that has available a bearing lug in which a metal sleeve is arranged. If the base body of the tensioning rail is produced, for example, from plastic, then, with the metal sleeve in the bearing lug, damage to the tensioning rail when fastening to an engine block or the like is prevented, because the metal sleeve is significantly more stable than the plastic material of the tensioning rail. For this purpose, the metal sleeve can be pressed or sunk into the bearing lug or extrusion coated with plastic.
Here, it is to be viewed as disadvantageous that additional tools are required, for example, for an ultrasonic fusing process, for inserting the sleeve into the bearing lug, so that the tensioning rail can also be produced only with considerable expense.